A dazed image rendering

OpenGL Development
#1

I have create a simple start exemple, folling some code of source tutorial, Start well, but create a confez image, distorced like below…

What can I do to fix it?

Thanks all!

#2

Please post source code.

It looks like you might not be clearing your color and depth buffers.

JW

#3

Thanks anarcotron, The code follows below…


package org.gldemos;

import org.lwjgl.LWJGLException;
import org.lwjgl.Sys;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.DisplayMode;
import org.lwjgl.opengl.GL11;

/**
 * @author inocencio
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public class init {
	
	private DisplayMode chosenModel = null;
	private boolean running = true;
	
	int width = 800;
	int height = 600;
	
	init() {
		
		try {
			
			DisplayMode[] modes = Display.getAvailableDisplayModes();
			
			for (int i=0; i < modes.length; i++) {
				
				if ((modes[i].getWidth() == width) && (modes[i].getHeight() == height)) {
					chosenModel = modes[i];
					break;
				}
			}
			
		}	catch(LWJGLException ex) {
			Sys.alert("Error", "Unable to determine display mode");
			System.exit(0);
			
		}
		
		if (chosenModel == null) {
			Sys.alert("Error","Unable to find display mode");
			System.exit(0);
		}
		
		try {
			Display.setDisplayMode(chosenModel);
			Display.setTitle("Example 01");
			Display.create();
		}	catch(LWJGLException ex) {
			Sys.alert("Error","Unable to create display");
			System.exit(0);
		}
		
		//seta um background
		GL11.glClearColor(0,0,0,0);
		
		runningGame();
			
	}
	
	public void runningGame() {
		
		float pos = 0.0f;
		
		//renderiza usando OpenGL
		
		while(running) {
			
			pos += 0.01f;
			GL11.glBegin(GL11.GL_QUADS);
	          GL11.glVertex3f(0,0,pos);
	          GL11.glVertex3f(1,0,pos);
	          GL11.glVertex3f(1,1,pos);
	          GL11.glVertex3f(0,1,pos);
	        GL11.glEnd();

	        Display.update();
	        
	        if (Display.isCloseRequested())
	        	running = false;
		}
		
		Display.destroy();
		System.exit(0);
	}

	public static void main(String[] args) {
		
		new init();
	}
}
#4

Yes you need to call GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT) prior to your rendering.

#5

I have put the line that you show me into main loop

		while(running) {
			GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);

			pos += 0.01f;
			GL11.glBegin(GL11.GL_QUADS);
	          GL11.glVertex3f(0,0,pos);
	          GL11.glVertex3f(1,0,pos);
	          GL11.glVertex3f(1,1,pos);
	          GL11.glVertex3f(0,1,pos);
	        GL11.glEnd();

	        Display.update();
	        
	        if (Display.isCloseRequested())
	        	running = false;
	        
	        if (Keyboard.isKeyDown(Keyboard.KEY_ESCAPE))
	        	running = false;
		}

The screen start and continues in full black. Vertex3f can render a Square or Triangle?

#6

Also in your code you never setup the projection matrix. This very same problem was discussed here:

http://192.18.37.44/forums/index.php?topic=10965.0

#7

Last but not least you never define the color…

You need the RedBook, shouldn’t be hard to find with Google.

#8

Thanks all. I will checkout the “RedBook”, its the real title?

#9

Red Book:

http://www.opengl.org/documentation/red_book_1.0/

#10

thaks for support me anarchotron! =D